Automobile manufacturers have been charged with providing increasing levels of safety, especially over the past 40 years. One of the more dramatic improvements in their safety endeavors was introduction of devices that serve to restrain a vehicle user's movement in the event of a violent collision. The first such devices were lap-type seatbelts. They were eventually followed by introduction of three point restraint systems that, in addition to a lap belt, further comprised a second belt that served to restrain movement of the vehicle user's upper torso in the event of a violent collision. They are generally positioned above and behind the user's shoulder regions. Such devices are now commonly referred to as shoulder restraints, shoulder restraint belts, shoulder straps, etc. The standards covering their use and capabilities are found in Federal Motor Vehicle Safety Standards 208, 209 and 210.
Starting in 1968 three point restraint systems were mandated for all automobiles sold in the United States. Such restraint systems were not required in trucks until 1972. Be that as it may, this implies that pre-1968 automobiles have, by today's standards, inadequate restraint devices. This circumstance is usually exacerbated by a general lack of padding on the steering wheels and dashboards of these earlier automobiles. Thus, using only lap-type seatbelts, a pre-1968 automobile user's upper torso is unrestrained and, hence, in the event of a collision, subject to severe impacts. Consequently, various shoulder restraint retrofit assemblies have been suggested for use in pre-1968 autos. Their use often involved adding an anchor (i.e., a strong seat belt attachment point) to a vertical frame member (e.g., a door frame member) of the auto in positions that are generally located above and outboard of (i.e., to the side of) the auto seat being serviced by such a vertical frame mounted safety belt. It might also be noted here that use of such vertical frame member mounting locations is, in the opinion of some auto safety experts, less preferred (from a safety point of view) relative to anchoring such torso restraining safety belts more inboard (i.e., more directly behind the user's shoulder) as opposed to anchoring them more outboard of (i.e., to the side of) the user's shoulder e.g., mounting them on a vertical door frame member).
Consequently, other prior art three point restraint retrofits involved drilling a hole in the automobile roof more directly behind the restraint user's shoulder. A bolt was then passed through the hole in the vehicle's sheet metal roof to provide a reliable shoulder restraint anchor point. Again, these anchor points were located more directly to the rear of the user's shoulder (relative to mounting the anchor on the auto's door frame). However, the bolt head of such systems (and usually a washer placed behind that bolt head) is readily visible above the outside roof surface of the vehicle. This circumstance creates an aesthetically displeasing outside appearance of the roofline of the vehicle.
Another fairly common three point restraint system that was located more to the rear of the user's shoulder involved welding an anchor (e.g., a metal plate) to the inside of a motor vehicle roof at a more inboard location. This type of retrofit device has several drawbacks. For example, the heat required to weld an anchor piece to the roof of a vehicle will seriously discolor and/or blister the roofs outer paint finish over a relatively wide area. Moreover, since the headliner and roof insulation of such vehicles will often melt or burn when exposed to welding temperatures, use of this anchoring method implies that the roof will have to be relatively more extensively repaired and repainted. Moreover, when welding is employed, the vehicle's flammable headliner materials (e.g., insulation) must be removed and reinstalled, or completely replaced. Additionally the strength of many such anchor welds (especially when carried out by non-professional welders) have proven to be inadequate in some high impact collision situations.
Next, it should be noted that the patent literature discloses several devices and methods for forming a cavity in a sheet of metal. Some of these are employed in automotive applications. For example, U.S. Pat. No. 4,295,765 teaches a tie-down structure 10 having (1) a body member 12, (2) a plug 14 and (3) a threaded member such as a nut. The body member 12 has a top wall 12a, an outwardly flaring side wall 12b and an externally threaded stem 12c. An axial, internally threaded, portion 12d extends partly within the body member 12. The body member 12 also is provided with a cavity 12e below the top wall 12a for receiving a tightening tool head such as a hex wrench. The plug 14 has an unthreaded axial passageway 14a that opens into an outwardly flaring inner wall 14b. This wall 14b is complementary in shape to the outwardly flaring side wall 12b of the body number 12.
U.S. Pat. No. 6,874,818 B2 teaches an energy absorbing seat belt anchorage system wherein, as shown in FIG. 4, said system has a nut 24 that is pressed against a transverse wall 28 of a housing 18 by a retainer washer 86. A bolt 38 will be tightened to draw a tapered side 36 of the nut 24 into firm surface-to-surface contact with a tapered surface 30 of the transverse wall 28 of the housing 18. Crush ribs 68 overlie the head 44 of the bolt 38. A shoulder 48 of a collar 46 is closely adjacent to the abutment ring 32. In a crash situation, and specifically when a side collision occurs, the bolt is forced outwardly as depicted in FIG. 6. The shoulder 48 of the collar 46 deforms and bends the abutment ring 32 outwardly. The crush ribs 68 crush against the head 44 of the bolt 38. The resistance of the abutment ring 32 to bending absorbs energy. The crushing of the ribs 68 contributes to the absorption of energy.
U.S. Pat. No. 6,641,229 B1 teaches that a boss pulled into a socket hole in a wheel under the action of a bolt on stud on the nose of the boss can cause plastic deformation in a metal sheet (e.g., a sheet made of steel).
U.S. Pat. No. 5,564,873 teaches a self-attaching fastener and method for its attachment wherein an installation head 70 receives a fastener element for installation in a metal panel 60. The installation head includes a nose member 72 having a bore 73 that, in turn, receives a reciprocal plunger 74. A free end of the plunger is driven against a driven surface 42 of the fastener 20. This action drives the free end of a barrel portion 26 into the panel 60. The plunger 74 includes a cylindrical piercing bore 75 that receives a piercing end 77 that pierces the panel.
U.S. Pat. No. 3,878,599 discloses a method for fastening a nut to a panel. The panel is deformed into a recess in the nut by advancing a punch against the panel. The punch is advanced into a tool receiving recess in the bottom of the recess beyond a panel edge.
U.S. Pat. No. 2,307,080 teaches a method of attaching panels to a framework. A panel to receive the fastening devices is provided with holes 4 that are counter-bored (see FIG. 7) to provide frusto-conical portions 5 and 6 for reception of a nut such as that shown in FIG. 11.
U.S. Pat. No. 3,053,300 teaches a fastener device wherein an anchor nut is mounted on a piece of sheet metal 30. A hole 32 is drilled in the sheet metal 30, and an annular shank 14 is inserted therein. A mounting tool is then used to deform the extremity 22 of the annular shank 14 over the periphery of the hole 32. This deforming step forces the lower surface of the periphery of the hole to conform to an underlying surface 16.